Wire electric discharge machine including profile adjusting mechanism

ABSTRACT

A wire electrical discharge machine in which a profile directing unit controls a profile of a portion in the neighborhood of an approach point, which connects an approach path portion with a machining profile portion of the relative movement path of the wire electrode and workpiece on a machined face of the workpiece. A profile of a portion in the neighborhood of the approach point on the machined face of the workpieces can be adjusted to a desired profile according to the use of the workpiece.

This application is a 371 of PCT/JP01/10326, filed Nov. 27, 2001.

TECHNICAL FIELD

The present invention relates to improvements in a wire electricdischarge machine to conduct machining on a workpiece when electricpower for machining is supplied between an electrode and the workpiece.

BACKGROUND ART

First of all, the formation of a recess portion on a machined face of aworkpiece by electric discharge machining will be explained below. FIG.6 is a schematic illustration showing a relative movement path, whichwill be referred to as an electrode path in this specificationhereinafter, formed between a wire electrode and workpiece in the caseof wire electric discharge machining. In the drawing, reference numeral1 is a workpiece, reference numeral 2 is a machined profile portion ofan electrode path to be machined to an objective profile (This machinedprofile portion of the electrode path will be referred to as a profileportion in this specification hereinafter.), reference numeral 3 is apoint at which a machining start hole is formed (This point will bereferred to as a machining start point in this specificationhereinafter.), reference numeral 4 is an approach path portion of theelectrode path formed from the machining start point 3 to the profileportion 2 (This approach path portion will be referred to as an approachportion in this specification hereinafter.), and reference mark O is aconnection point of the profile portion 2 with the approach portion 4(This connection point will be referred to as an approach point in thisspecification hereinafter.). FIG. 7 is an enlarged view of theneighborhood of approach point O shown in FIG. 6. Like referencecharacters are used to indicate like parts in FIGS. 6 and 7. In FIG. 7,reference numeral 5 is a wire electrode, and reference numeral 6 is arecess portion.

As well known, wire electric discharge machining is a method ofmachining in which the wire electrode 5 is used as if it were a fretsawto cut out the workpiece 1. In the process of wire electric dischargemachining, not only the profile portion 2 but also the approach portion4 is machined as shown in FIG. 6.

In the profile portion 2 of usual wire electric discharge machining,consideration must be given to a radius of the wire electrode 5,electric discharge gap and allowance necessary for finishing. Therefore,a path is set which is distant from the profile to be machined by apredetermined distance which is referred to as an offset, and electricdischarge machining is conducted when the center of the wire electrode 5is moved along this offset path. As shown in FIG. 7, the wire electrode5 starts at the machining start point 3 and passes through the approachportion 4 and then moves from approach point O to the profile portion 2and makes a round of the profile portion 2 and then returns to themachining start point 3 via the approach point O and the approachportion 4.

When the wire electrode 5 moves as described above and makes a round ofthe profile portion 2, the wire electrode 5 passes through the profileportion 2 only once except for approach point O, that is, the wireelectrode 5 passes through only approach point O twice. When theelectrode 5 passes through approach point O for the second time, theportion of the workpiece 1 to be removed has already been removed.Therefore, when the electrode 5 passes through approach point O for thesecond time, electric discharge is generated on the face which hasalready been machined, and overcutting is caused on the machined face.Accordingly, the recess portion 6 is formed in the neighborhood ofapproach point O on the machined face of the workpiece 1.

In the case of conducting wire electric discharge machining on aworkpiece so as to make a metallic mold for resin molding, resin moldingis conducted with the metallic mold by transferring the profile formedby electric discharge machining. Therefore, when the recess portion 6exists on the machined face of the metallic mold which is machined as aworkpiece of wire electric discharge machining, an unexpected pattern isformed on a resin product made by this metallic mold. In order to solvethis problem, it is necessary to form a uniform profile of the metallicmold having no recess portion 6. Therefore, it is necessary to removethe recess portion 6, which has been formed on the machine face of theworkpiece as shown in FIG. 7, by after-machining such as wire electricdischarge machining. In this case, it is necessary to remove the entirevolume of a hatched portion in FIG. 8 from the workpiece 1.

As a method of suppressing the generation of the recess portion 6,Japanese Unexamined Patent Publication No. 4-189421 discloses a wireelectric discharge machining method. According to this method, as shownin FIG. 9, the first approach point OA and the second approach point OBare set on the profile portion 2, and the approach path is connectedwith these two approach points, that is, the approach portions 4A and 4Bare connected with these two approach points, and the electric dischargemachining program is changed so that an electrode path in the profileportion between approach points OA and OB in FIG. 9 can be deleted. Inthis way, the electrode path is changed as shown in FIG. 9.

Further, as a method of suppressing the generation of the recess portion6, International Patent Application No. PCT/JP01/09577 discloses aninvention. According to this invention, two approach points are not set,and the electrode path is formed in the same manner as that shown inFIG. 7. When a distance between approach point 0, at which the approachportion 4 and the profile portion 2 of the electrode path are connectedwith each other, and the center of the wire electrode 5 in the profileportion 2 is in a range in which a machining volume of the workpiece 1per unit moving distance of the wire electrode 5 is decreased, electricdischarge machining is conducted when an intensity of energy ofmachining per unit moving distance of the wire electrode 5 is decreased.

In the case where the workpiece is a metallic mold used for resinforming, when the recess portion 6 shown in FIG. 7 is not formed but theprotruding portion 7 shown in FIG. 10 is formed, it is unnecessary toremove the entire volume of a hatched portion in FIG. 8, that is, onlythe protruding portion 7 shown in FIG. 10 may be removed. Therefore, thetime required for after-machining can be greatly reduced. In this way,the profile of a portion in the neighborhood of approach point O of theworkpiece 1 may be positively formed into a protrusion in some cases.

In the case where the workpiece is a metallic die used for pressforming, if the protruding portion 7 shown in FIG. 10 is formed in theneighborhood of approach point O of the workpiece 1, the protrudingportion 7 collides with the punch in the process of press forming andthe metallic die is damaged. Therefore, it is necessary to remove theprotruding portion 7, however, in the case of a metallic die used forpress forming in which after-machining is unnecessary, a recess portionlike the recess portion 6 shown in FIG. 7 may exist.

The invention disclosed in Japanese Unexamined Patent Publication No.4-189421 and the invention disclosed in International Patent ApplicationNo. PCT/JP01/09577 have a predetermined effect to suppress the formationof the recess portion 6 described above, however, it is impossible todesirably adjust the profile of a portion in the neighborhood of theapproach point on a machined face of a workpiece.

DISCLOSURE OF INVENTION

The present invention has been accomplished to solve the above problems.It is an object of the present invention to provide a wire electricdischarge machine capable of adjusting a profile of a portion in theneighborhood of an approach point on a machined face of a workpiece sothat it can be formed into a desired profile.

The present invention provides a wire electric discharge machine inwhich a wire electrode and workpiece are relatively moved from eachother by a drive means and energy for machining is supplied between thewire electrode and workpiece by a machining electric power supply meansso that the workpiece is machined by electric discharge generatedbetween the wire electrode and workpiece, the wire electric dischargemachine comprising: a profile directing means for directing a profile ofa portion in the neighborhood of an approach point, which connects anapproach path portion with a machining profile portion of the relativemovement path on a machined face of the workpiece, to be a desirableprofile such as a protruding profile or recess profile according to theuse of the workpiece; and an adjusting means for adjusting a profile ofthe portion in the neighborhood of the approach point according to thedirection value directed by the profile directing means.

In the wire electric discharge machine of the present invention, theadjusting means is a machining energy adjusting coefficient settingmeans for increasing and decreasing energy for machining.

The present invention provides a wire electric discharge machine inwhich a wire electrode and workpiece are relatively moved from eachother by a drive means and energy for machining is supplied between thewire electrode and workpiece by a machining electric power supply meansso that the workpiece is machined by electric discharge generatedbetween the wire electrode and workpiece, the wire electric dischargemachine comprising: a machining energy adjusting means for suppressingthe formation of a recess portion in the neighborhood of the approachpoint on the machined face of the workpiece by reducing an intensity ofmachining energy per unit moving distance of the wire electrode when adistance between the approach point, at which the approach path portionand the machining profile portion of the electrode path are connectedwith each other, and the center of the wire electrode in the machiningprofile portion is in a range in which a machining volume of theworkpiece per unit moving distance of the wire electrode is decreased; aprofile directing means for directing a profile of a portion in theneighborhood of an approach point on the machined face of the workpieceto be a desirable profile such as a protruding profile or recess profileaccording to the use of the workpiece; and a machining energy adjustingcoefficient setting means for adjusting a profile of a portion in theneighborhood of the approach point on the machined face of the workpieceaccording to a direction value directed by the profile directing means,wherein when a machining energy setting value of the machining energyadjusting means for suppressing the formation of a recess portion in theneighborhood of the approach point on the machined face of the workpieceis increased and decreased by the machining energy adjusting coefficientsetting means, a desired protruding profile or recess profile is formedin a portion in the neighborhood of the approach point on the machinedface of the workpiece.

The present invention provides a wire electric discharge machine inwhich a wire electrode and workpiece are relatively moved from eachother by a drive means and two different approach points (a firstapproach point and a second approach point) to connect an approach pathportion with a machining profile portion of the relative moving path areset and a portion of the relative moving path of the machining profileportion between the two approach points is deleted so that electricdischarge machining is conducted on a machining profile portion of therelative moving path from the first approach point to the secondapproach point, the wire electric discharge machine comprising: aprofile directing means for directing a profile of a portion in theneighborhood of an approach point to be a desirable profile such as aprotruding profile or recess profile according to the use of aworkpiece; and an approach point interval adjusting means for adjustingan interval between the first approach point and the second approachpoint according to a direction value given by the profile directingmeans.

Since the wire electric discharge machine of the present invention iscomposed as described above, it is possible to provide an effect that aprofile of a portion in the neighborhood of an approach point on amachined face of a workpiece can be adjusted to be a desired profileaccording to the use of a workpiece.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic illustration showing an arrangement of a wireelectric discharge machine of Embodiment 1 of the present invention.

FIG. 2 is a schematic illustration showing an example of the profiledirecting means.

FIG. 3 is a schematic illustration showing an example of the machiningenergy adjusting coefficient conversion table.

FIG. 4 is a schematic illustration showing an arrangement of a wireelectric discharge machine of Embodiment 2 of the present invention.

FIG. 5 is a schematic illustration showing an example of the approachpoint interval conversion table.

FIG. 6 is a schematic illustration showing an electrode path in the caseof conducting wire electric discharge machining.

FIG. 7 is an enlarged view of a portion in the neighborhood of theapproach point shown in FIG. 6.

FIG. 8 is a schematic illustration showing a range in which a recessportion on a machined face of a workpiece is removed by after-machining.

FIG. 9 is a schematic illustration showing an electrode path of theprior art in which the formation of a recess portion on a machined faceof a workpiece is suppressed by changing the electrode path so that theelectrode path in the profile portion between two approach points isdeleted.

FIG. 10 is a schematic illustration showing an example in which aprotruding portion is formed in the neighborhood of an approach point ona machined face of a workpiece.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1

FIG. 1 is a schematic illustration showing an arrangement of a wireelectric discharge machine of Embodiment 1 of the present invention. Inthe drawing, reference numeral 1 is a workpiece, reference numeral 5 isa wire electrode, reference numeral 8 is a wire electrode supply means,reference numeral 9 is a machining solution supply means, referencenumeral 10 is a drive means, reference numeral 11 is a machiningelectric power supply means, reference numeral 12 is a control means,reference numeral 13 is a machining energy adjusting means, referencenumeral 14 is a machining energy inputting ratio table, referencenumeral 15 is a profile directing means for directing a profile of aportion in the neighborhood of an approach point on a machined face ofthe workpiece 1 to be a desirable profile such as a protruding profileor recess profile according to the use of the workpiece 1, referencenumeral 16 is a machining energy adjusting coefficient setting means foradjusting a profile of a portion in the neighborhood of the approachpoint on the machined face of the workpiece 1 according to the directionvalue directed by the profile directing means 15, and reference numeral17 is a machining energy adjusting coefficient conversion table.

In the same manner as that of the invention of International PatentApplication No. PCT/JP01/09577, the wire electric discharge machine ofEmbodiment 1 of the present invention as shown in FIG. 1 has a functionof suppressing the formation of a recess portion on the machined face ofthe workpiece 1 by reducing machining energy when the wire electrodecomes close to the approach point.

In FIG. 1, the wire electrode supply means 8 gives an appropriateintensity of tension to the wire electrode 5 while the wire electrodesupply means 8 is letting out the wire electrode 5 and making it run ata predetermined speed. The machining solution supply means 9 supplied amachining solution between the wire electrode 5 and the workpiece 1. Themachining electric power supply means 11 impresses a pulse-shapedvoltage between the electrodes so that electric discharge can begenerated.

The machining energy adjusting means 13 recognizes a position of theapproach point at which the setting of offset is released from theprogram describing an electrode path, which is accommodated in thecontrol unit 12, according to the setting information of offset. Themachining energy adjusting means 13 has the following function. Adistance between the coordinate of an approach point, at which thesetting of offset is released during the process of machining, and thecoordinate of the present wire electrode center in the machining profileportion of the electrode path is calculated. Then, a ratio of machiningenergy for suppressing the formation of a recess portion in theneighborhood of the approach point is found with the machining energyinputting table 14, and a parameter is changed so that machining energycan be reduced at a predetermined ratio with respect to the machiningelectric power supply means 11.

FIG. 2 is a schematic illustration showing an example of the profiledirecting means 15. FIG. 2 shows a case in which a slide bar is used.This slide bar is displayed on a display means such as CRT not shown inthe drawing, and the indicating section 15 a is moved to the right andleft by drugging operation conducted by, for example, a mouse. In thisway, an operator can direct the degree of adjusting machining energy. Anindication value indicated by the indicating section 15 a is sent to themachining energy adjusting coefficient setting means 16. According tothe indicating value which has been sent in this way, the machiningenergy adjusting coefficient setting means 16 finds machining energyadjusting coefficient H1, for example, with the machining energyadjusting coefficient conversion table 17 shown in FIG. 3, and the thusfound machining energy adjusting coefficient H1 is sent to the machiningenergy adjusting means 13. The machining energy adjusting means 13changes a parameter so that the machining electric power supply means 11can output an intensity of machining energy to be outputted when themachining energy value is multiplied by machining energy adjustingcoefficient H1 which has been sent from the machining energy adjustingcoefficient setting means 16.

For example, in the case where the machining energy adjustingcoefficient conversion table 17 shown in FIG. 3 is set, when theindicating value of the slide bar in the indicating section 15 a is 0,the parameter is changed as follows. Since machining energy adjustingcoefficient H1, which is sent to the machining energy adjusting means 13by the machining energy adjusting coefficient setting means 16, is 1,the machining energy adjusting means 13 multiplies the machining energyvalue by a value which is obtained when a ratio of machining energy forsuppressing the formation of a recess portion in the neighborhood of theapproach point on the machining energy inputting ratio table 14 ismultiplied by 1. That is, the machining energy value is multiplied by aratio of machining energy for suppressing the formation of a recess inthe neighborhood of an approach point on the machining energy inputtingratio table 14. In this way, the parameter is changed so that machiningenergy to be inputted can be outputted from the machining electric powersupply means 11. Accordingly, machining energy is inputted so that theformation of a recess portion in the neighborhood of the approach pointcan be suppressed.

In the case where an indicating value of the slide bar in the indicatingsection 15 a is +2, since machining energy adjusting coefficient H1,which is sent by the machining energy adjusting coefficient settingmeans 16 to the machining energy adjusting means 13, is 0.6, themachining energy adjusting means 13 multiplies the machining energyvalue by a value which is obtained when a ratio of machining energy forsuppressing the formation of a recess portion in the neighborhood of theapproach point on the machining energy inputting ratio table 14 isfurther multiplied by 0.6. In this way, the parameter is changed so thatmachining energy to be inputted can be outputted from the machiningelectric power supply means 11. Accordingly, since an intensity ofmachining energy to be inputted is lower than an intensity of machiningenergy for suppressing the formation of a recess portion in theneighborhood of the approach point, a volume of machining is decreased,and a protruding profile shown in FIG. 10 is formed in the neighborhoodof the approach point on the machined face of the workpiece.

In the case where an indicating value of the slide bar in the indicatingsection 15 a is −1, since machining energy adjusting coefficient H1,which is sent by the machining energy adjusting coefficient settingmeans 16 to the machining energy adjusting means 13, is 1.2, themachining energy adjusting means 13 multiplies the machining energyvalue by a value which is obtained when a ratio of machining energy forsuppressing the formation of a recess portion in the neighborhood of theapproach point on the machining energy inputting ratio table 14 isfurther multiplied by 1.2. In this way, the parameter is changed so thatmachining energy to be inputted can be outputted from the machiningelectric power supply means 11. Accordingly, since an intensity ofmachining energy to be inputted is higher than an intensity of machiningenergy for suppressing the formation of a recess portion in theneighborhood of the approach point, a volume of machining is increased,and a recess profile shown in FIG. 7 is formed in the neighborhood ofthe approach point on the machined face of the workpiece.

As described above, according to the use of the workpiece, when it isintended by an operator to form a protruding profile in the neighborhoodof the approach point on the machined face of the workpiece, theoperator indicates a positive indicating value by the profile indicatingmeans 15. When it is intended to form a recess profile in theneighborhood of the approach point on the machined face of theworkpiece, the operator indicates a negative indicating value by theprofile indicating means 15. Due to the foregoing, it is possible toadjust a profile of the portion in the neighborhood of the approachpoint on the machined face of the workpiece to be a desired profile.

The above explanations are made into a case in which an intensity ofmachining energy is adjusted by the machining energy adjusting means 13while the machining energy inputting ratio table 14, profile indicatingmeans 15, machining energy adjusting coefficient conversion table 17 andmachining energy adjusting coefficient setting means 16 are being used.However, the following method may be adopted instead of the abovemethod. By a table in which the machining energy inputting ratio table14 and the machining energy adjusting coefficient table 17 are combinedwith each other, a machining energy adjusting coefficient correspondingto the indicating value by the profile indicating means 15 is set by theenergy adjusting coefficient setting means 16, and an intensity ofmachining energy is adjusted by the machining energy adjusting means 13.

Embodiment 2

FIG. 4 is a schematic illustration showing an arrangement of a wireelectric discharge machine of Embodiment 2 of the present invention.Like reference characters are used to indicate like parts in FIG. 1showing Embodiment 1 and FIG. 4 showing Embodiment 2. In FIG. 4,reference numeral 18 is an automatic program converting means, referencenumeral 19 is an approach point interval adjusting means which is anadjusting means for adjusting a profile of a portion in the neighborhoodof an approach point on a machined face of a workpiece 1 according to anindicating value by the profile indicating means 15, and referencenumeral 20 is an approach point interval conversion table.

In the same manner as that of the wire electric discharge machinedisclosed in Japanese Unexamined Patent Publication No. 4-189421, thewire electric discharge machine shown in FIG. 4 of Embodiment 2 of thepresent invention has a function of suppressing the formation of arecess portion on a machined face of a workpiece 1 in a portion in theneighborhood of an approach point by the electrode path shown in FIG. 9.

When machining is conducted as shown in FIG. 6, the automatic programconversion means 18 extracts approach point O from the programdescribing the electrode path accommodated in the control means 12according to the offset setting information and grasps the approachportion 4 and the profile portion 2. Next, as shown in FIG. 9, the firstapproach point OA and the second approach point OB are set in theprofile portion 2, and the path of the approach portion is connectedwith these two approach points, that is, the approach portions 4A and 4Bare connected with these two approach points, and the program is changedso that the electrode path between these two approach points can bedeleted, that is, a portion between the approach points OA and OB inFIG. 9 can be deleted, and the thus changed program is accommodated inthe control means 12 again.

That is, when the electrode path in the neighborhood of the approachpoint has become an electrode path shown in FIGS. 6 and 7, the electrodepath is changed as shown in FIG. 9. The control means 12 drives thedrive means 10, and the wire electrode 5 and the workpiece 1 arerelatively moved from each other along the thus changed electrode path.

As described above, by the automatic program conversion means 18, thereare provided a first approach point OA at which the wire electrode 5passes when it enters the profile portion 2 from the approach portion 4Awith respect to the electrode path program and a second approach pointOB at which the wire electrode 5 passes when it returns from the profileportion 2 to the approach portion 4B, and the program is changed so thatthe wire electrode 5 can not pass through the profile portion betweenthese two approach points. Due to the foregoing, the formation of arecess portion on the machined face of the workpiece 1 can besuppressed.

In the case where the same slide bar as that of Embodiment 1 shown inFIG. 2 is used as the profile indicating means 15, an indicating valueindicated by the indicating section 15 a is sent to the approach pointinterval adjusting means 19. According to the thus sent indicatingvalue, the approach point interval adjusting means 19 uses, for example,the approach point interval conversion table 20 shown in FIG. 5 andfinds approach point interval adjusting coefficient H2, and the thusfound approach point interval adjusting coefficient H2 is sent to theautomatic program conversion means 18.

For example, in the case where the approach point interval conversiontable 20 shown in FIG. 5 is set, when the indicating value of the slidebar of the indicating section 15 a is 0, approach point intervaladjusting coefficient H2, which is sent to the automatic programconversion means 18 by the approach point interval adjusting means 19,is 1. Therefore, the approach point interval is not adjusted by theautomatic program conversion means 18, and the approach point intervalto suppress the formation of a recess portion in the neighborhood of theapproach point is set and machining is conducted on the workpiece.

In the case where the indicating value of the slide bar of theindicating section 15 a is +2, approach point interval adjustingcoefficient H2, which is sent to the automatic program conversion means18 by the approach point interval adjusting means 19, is 1.4. Therefore,the approach interval which is set by the automatic program conversionmeans 18 is extended by 1.4 times and machining is conducted.Accordingly, since this approach point interval is longer than theapproach point interval to suppress the formation of a recess portion inthe neighborhood of the approach point, the machining volume isdecreased and the protruding profile shown in FIG. 10 is formed in theneighborhood of the approach point on the machined face of theworkpiece.

In the case where the indicating value of the slide bar of theindicating section 15 a is −1, approach point interval adjustingcoefficient H2, which is sent to the automatic program conversion means18 by the approach point interval adjusting means 19, is 0.8. Therefore,the approach interval which is set by the automatic program conversionmeans 18 is extended by 0.8 time and machining is conducted.Accordingly, since this approach point interval is shorter than theapproach point interval to suppress the formation of a recess portion inthe neighborhood of the approach point, the machining volume isincreased and the recess profile shown in FIG. 7 is formed in theneighborhood of the approach point on the machined face of theworkpiece.

As described above, when an operator wants to form a protruding profilein the neighborhood of the approach point on the machined face of theworkpiece by the profile indicating means 15 according to the use of theworkpiece, the operator indicates a positive indicating value. When anoperator wants to form a recess profile in the neighborhood of theapproach point on the machined face of the workpiece by the profileindicating means 15 according to the use of the workpiece, the operatorindicates a negative indicating value. In this way, the profile of aportion in the neighborhood of the approach point on the machined faceof the workpiece can be adjusted to a desired profile.

The above explanations are made into a case in which a slide bardisplayed on a display means such as CRT is used as the profileindicating means 15, however, a mechanically composed slide bar may beused. Alternatively, the profile indicating means 15 may be composed ofa mechanical switch, volume or touch panel. Further, the profileindicating means 15 may be composed in such a manner that a profile of aportion in the neighborhood of the approach point on the machined faceof the workpiece is adjusted by the numerical inputting.

Further, the profile indicating means 15 may be composed of NC programcodes, and a profile of a portion in the neighborhood of the approachpoint on the machined face of the workpiece may be adjusted according toan indicating value indicated by these NC program codes.

A profile of the machined face of the workpiece corresponding to theindicating value of the profile indicating means 15 can be displayed ona display means such as CRT by a two-dimensional or three-dimensionalprofile. Due to the above structure, the operator can easily recognizean indicating value and a profile of the machined face of the workpieceafter the completion of machining corresponding to this indicatingvalue. Therefore, the operator can easily set a desired profile.

INDUSTRIAL APPLICABILITY

As described above, the wire electric discharge machine of the presentinvention is appropriately used for wire electric discharge machining.

What is claimed is:
 1. A wire electric discharge machine in which a wireelectrode and workpiece are relatively moved by a drive means and energyfor machining is supplied between the wire electrode and workpiece by amachining electric power supply means so that the workpiece is machinedby electric discharge, the wire electric discharge machine comprising: aprofile directing means for directing a profile of a portion in aneighborhood of an approach point, which connects an approach pathportion with a machining profile portion of a relative movement path ona machined face of the workpiece, to be a desirable profile such as aprotruding profile or recess profile according to the use of theworkpiece; and an adjusting means for adjusting the profile of theportion in the neighborhood of the approach point according to adirection value directed by the profile directing means.
 2. A wireelectric discharge machine according to claim 1, wherein the adjustingmeans is a machining energy adjusting coefficient setting means forincreasing and decreasing energy for machining.
 3. A wire electricdischarge machine in which a wire electrode and workpiece are relativelymoved by a drive means and energy for machining is supplied between thewire electrode and workpiece by a machining electric power supply meansso that the workpiece is machined by electric discharge, the wireelectric discharge machine comprising: a machining energy adjustingmeans for suppressing a formation of a recess portion in a neighborhoodof an approach point on a machined face of the workpiece by reducing anintensity of machining energy per unit moving distance of the wireelectrode when a distance between the approach point, at which anapproach path portion and a machining profile portion of an electrodepath are connected with each other, and a center of the wire electrodein the machining profile portion is in a range in which a machiningvolume of the workpiece per unit moving distance of the wire electrodeis decreased; a profile directing means for directing a profile of aportion in the neighborhood of the approach point on the machined faceof the workpiece so that it can be a desirable profile such as aprotruding profile or recess profile according to the use of theworkpiece; and a machining energy adjusting coefficient setting meansfor adjusting the profile of the portion in the neighborhood of theapproach point on the machined face of the workpiece according to adirection value directed by the profile directing means, wherein when amachining energy setting value of the machining energy adjusting meansfor suppressing the formation of the recess portion in the neighborhoodof the approach point on the machined face of the workpiece is increasedand decreased by the machining energy adjusting coefficient settingmeans, a desired protruding profile or recess profile is formed in theportion in the neighborhood of the approach point on the machined faceof the workpiece.
 4. A wire electric discharge machine in which a wireelectrode and workpiece are relatively moved by a drive means, and afirst approach point and a second approach point are set to connectapproach path portions with a machining profile portion of the relativemoving path, respectively, the wire electric discharge machinecomprising: a profile directing means for directing a profile of aportion in the neighborhood of the approach points to be a desirableprofile such as a protruding profile or recess profile according to theuse of the workpiece; and an approach point interval adjusting means foradjusting an interval between the first approach point and the secondapproach point according to a direction value given by the profiledirecting means.
 5. A wire electric discharge machine in which a wireelectrode and workpiece are relatively moved by a drive section andenergy for machining is supplied between the wire electrode andworkpiece by a machining electric power supply section so that theworkpiece is machined by electric discharge, the wire electric dischargemachine comprising: a profile directing section for directing a profileof a portion in a neighborhood of an approach point, which connects anapproach path portion with a machining profile portion of a relativemovement path on a machined face of the workpiece, to be a desirableprofile such as a protruding profile or recess profile according to theuse of the workpiece; and an adjusting section for adjusting the profileof the portion in the neighborhood of the approach point according to adirection value directed by the profile directing section.
 6. A wireelectric discharge machine according to claim 5, wherein the adjustingsection is a machining energy adjusting coefficient setting section forincreasing and decreasing energy for machining.
 7. A wire electricdischarge machine in which a wire electrode and workpiece are relativelymoved by a drive section and energy for machining is supplied betweenthe wire electrode and workpiece by a machining electric power supplysection so that the workpiece is machined by electric discharge, thewire electric discharge machine comprising: a machining energy adjustingsection for suppressing a formation of a recess portion in aneighborhood of an approach point on a machined face of the workpiece byreducing an intensity of machining energy per unit moving distance ofthe wire electrode when a distance between the approach point, at whichan approach path portion and a machining profile portion of an electrodepath are connected with each other, and a center of the wire electrodein the machining profile portion is in a range in which a machiningvolume of the workpiece per unit moving distance of the wire electrodeis decreased; a profile directing section for directing a profile of aportion in the neighborhood of the approach point on the machined faceof the workpiece so that it can be a desirable profile such as aprotruding profile or recess profile according to the use of theworkpiece; and a machining energy adjusting coefficient setting sectionfor adjusting the profile of the portion in the neighborhood of theapproach point on the machined face of the workpiece according to adirection value directed by the profile directing section, wherein whena machining energy setting value of the machining energy adjustingsection for suppressing the formation of the recess portion in theneighborhood of the approach point on the machined face of the workpieceis increased and decreased by the machining energy adjusting coefficientsetting section, a desired protruding profile or recess profile isformed in the portion in the neighborhood of the approach point on themachined face of the workpiece.
 8. A wire electric discharge machine inwhich a wire electrode and workpiece are relatively moved by a drivesection and a first approach point and a second approach point are setto connect approach path portions with a machining profile portion ofthe relative moving path, respectively, the wire electric dischargemachine comprising: a profile directing section for directing a profileof a portion in the neighborhood of the approach points to be adesirable profile such as a protruding profile or recess profileaccording to the use of the workpiece; and an approach point intervaladjusting section for adjusting an interval between the first approachpoint and the second approach point according to a direction value givenby the profile directing section.